We report on the detection of anhydrous hydrochloric acid ( hydrogen chlorine , HCl ) in the carbon-rich star IRC+10216 using the spectroscopic facilities onboard the \it { Herschel } satellite .
Lines from J=1-0 up to J=7-6 have been detected .
From the observed intensities , we conclude that HCl is produced in the innermost layers of the circumstellar envelope with an abundance relative to H _ { 2 } of 5 \times 10 ^ { -8 } and extends until the molecules reach its photodissociation zone .
Upper limits to the column densities of AlH , MgH , CaH , CuH , KH , NaH , FeH , and other diatomic hydrides have also been obtained .